A terahertz imaging system using high $T_{c}$ superconducting oscillators fabricated from the Bi2212 single crystals*

We have developed a terahertz (THz) oscillator based on high $T_{c}$ superconductor of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$(Bi2212) single crystals\footnote{L. Ozyuzer \textit{et al.}, Science \textbf{318} (2007) 1291.} and have succeeded in developing 30$\mu $W level of output power,\footnote{S. Sekimoto \textit{et al.}, Appl. Phys. Lett. \textbf{130} (2013) 023703.} which is continuous, monochromatic as well as stable at frequencies between 0.3 $\sim$ 1.0 THz.\footnote{T. Kashiwagi \textit{et al.}, Jpn. J. Appl. Phys. \textbf{51} (2012) 010113.} Recently, for the purpose of application use of our THz oscillator, we have developed the reflection type of the imaging system in addition to the transmission imaging system reported previously.\footnote{M. Tsujimoto \textit{et al.}, J. Appl. Phys. \textbf{111} (2012) 123111.} We will show the details of the system and the images obtained here as practical example and compared those with previous results.